1. Field
The present invention relates to a system and a method for reconfiguring the source of propulsion of a vehicle comprising multiple propulsion systems.
2. Description of the Related Art
Hybrid and plug-in hybrid vehicles (HEV) present a useful combination of two forms of vehicular propulsion within the same vehicle, such as a combustion engine system and an electric system. In principle, by providing more than one system for vehicle propulsion, reliability and robustness of the overall vehicle propulsion system should be increased. If a failure occurs in a first propulsion system it should be possible to provide vehicular mobility from a second propulsion system. This is not always the case.
Current technologies sometimes provide various limp-home vehicle modes when a fault is detected within a portion of the hybrid vehicle's propulsion system. For example, if a fault is detected within an electric motor-generator portion of the hybrid vehicle, placing the vehicle into a limp-home mode may cause vehicle propulsion to be provided by the combustion engine system only.
Even if a split configuration HEV was configured to operate in these limp-home modes, this feature can be improved. Using a limp-home mode, if a fault is detected within the electric system of a HEV, then the combustion engine system of the HEV will activate and be the sole propulsion-generating system of the hybrid vehicle until the fault is repaired. This means that the entire electric system of the hybrid vehicle is unavailable. This is not always necessary, and it may be beneficial for a hybrid vehicle in this state to utilize some aspects of the electric motor-generator. For example, in this state, an HEV could still operate in a partial hybrid mode, thus requiring less fuel and/or placing less strain on the engine. Continuing the example, let's further assume that a cylinder of the internal combustion engine is not functioning properly. Any current limp-mode technology would simply eliminate the internal combustion engine system.
Furthermore, the user of the HEV may have a preference of mobility modes when a fault is detected. For example, the user may want to prevent strain on a particular portion of the propulsion system, or the user may want to save fuel and/or charge. This is particularly true if the stored fuel levels and/or the state of charge are low and the vehicle is not near a fuel, plugin or repair station. Current systems do not allow for any user input when changing the propulsion source of the hybrid vehicle after a fault is detected.
Thus, there is a need for methods and systems for reconfiguring hybrid vehicle systems with minimum mobility modes.